This invention relates generally to a steady rest for use in conjunction with a machine tool for supporting a rotating cylindrical workpiece and more particularly to a steady rest for use in conjunction with an O.D. grinding machine having a grinding wheel for removing material from the periphery of the workpiece.
As a grinding wheel is advanced and maintained in machining contact with the rotating workpiece, the grinding wheel exerts a relatively high bending force on the workpiece. This force tends to bend the workpiece away from the grinding wheel and induce a high frequency oscillation in the workpiece. Under these conditions, the outside periphery of a finished workpiece that has not been properly supported will be tend to be non-cylindrical and out-of-round. Externally supporting the workpiece on its outside diameter, in a direction generally opposing the force of the grinding wheel, significantly reduces the detrimental bending and high frequency oscillations of the workpiece.
Supporting a rotating workpiece is particularly difficult where, as is often the case in an O.D. grinding operation, the area that must be supported in order to adequately counteract the forces exerted by the grinding wheel is continuously changing in diameter. Prior steady rests require manual adjustment to initially bring a support rod or other support member into supporting contact with the outside diameter of the workpiece. Prior steady rests also require substantially continuous manual re-adjustment of the support rod during machining of the workpiece to maintain support as the diameter of the workpiece decreases. Moreover, these discrete adjustments of the support rod, to support a continuously changing surface, allow detrimental bending and high frequency oscillation of the workpiece during those times when the support rod may not be in intimate contact with the workpiece.